The present invention relates to metal-oxide-semiconductor field effect transistors (MOSFET) controlled based on sensed chemical characteristics, and more particularly to applying an AC signal to a backgate of a MOSFET to modulate a signal generated based on a sensed chemical characteristic.
Metal-oxide-semiconductor field effect transistors (MOSFET) with chemically sensitive gates or with chemically sensitive electrodes connected to gates are used in gas sensors, ion sensors, bio sensors, etc. However, since chemical signals have a very low frequency, so as to correspond to a substantially direct current (DC) voltage level, measurements are susceptible to MOSFET flicker noise.